These teachings relate generally to Reconstruction of images, and, more particularly, to reconstruction of images involving an inverse problem.
One exemplary instance of the reconstruction of images is reconstruction of ECT images.
Emission computed tomography (ECT) is an important scientific and medical imaging technique that can be divided into two branches: positron emission tomography (PET) and single-photon emission computed tomography (SPECT). Clinical applications of ECT include the detection, staging and monitoring response to therapy of cancer, detection and risk stratification of cardiovascular diseases, mapping of regional blood flow in the brain, bone scans, pulmonary ventilation/perfusion scans, renal scans and many others. In the nuclear medicine ECT examination a patient is administered a radiotracer that has adequate specificity and sensitivity for a given clinical detection task. The SPECT or PET camera counts photons that were recorded in discrete detector bins at various spatial locations, typically distributed 360 degrees about the patient. The reconstruction process attempts to estimate mean radiotracer activity distribution (ƒ) inside the body of a patient.
There is a great need to reduce radiation dose to the patients undergoing ECT examinations. This could be accomplished by lowering the total amount of activity in the radiotracer administered. However, lowering the total amount of activity in the radiotracer administered would lead to very high Poisson noise in the raw ECT data. In turn, such very noisy data if treated by the conventional ECT reconstruction techniques, e.g. FBP, MLEM, MAP-EM, OSL, OSEM, or RBBI, would lead to very noisy and clinically unacceptable reconstructed images.
There is a need for ECT reconstruction techniques that can provide good quality ECT reconstructions from low-dose ECT examinations.
There is also a need for image reconstruction techniques that can provide good quality image reconstructions under high noise conditions.